A single-number rating for sound attenuation of a suspended ceiling sharing a common ceiling plenum above adjacent rooms, as calculated by reference to EN ISO 717-1.
Dncw values remain valid although Dnfw, which is essentially the same as Dncw, has superseded it.

The intensity of sound generated by rainfall on building elements, such as lightweight roof constructions, which radiates into the room below (Please contact your Armstrong Technical team for more details).